The cooling capacity of coconut oil, palm oil, and petroleum oil were determined by solving the inverse problem (IP) using the newly developed commercial code, IQLab. It was shown that all of the oils exhibited shock-film-boiling, film-boiling, and convection-heat-transfer modes during the quenching process. The results of these investigations are necessary when developing a global database of the cooling capacity of different quenchants. The results obtained by solving the inverse problem are compared with simplified calculation results based on cooling time–temperature data obtained by using a multi-thermocouple Inconel 600 probe. The results obtained showed that the results from both methods agreed within ±10 %. These results suggest that the standard Inconel 600 probe can be used in many cases for determining average heat-transfer coefficients occurring when using vegetable oils, such as coconut oils, palm oils, and petroleum oils as quenchants.